Tool for trimming piston rings and the like



TOOL FOR TRIMMING PISTON RINGS AND THE LIKE Filed Oct. 9, 1954 HIV /Av "1..., --lllllllllllllll 9M; ZM fm @l ATTORNEYS Patented Sept. 22, 1936 N UNITED STATES; lMEN'r formicav John ziuiox, orchard Park, N. Y. Application October 9, 1934, Serial No. 747,602

i s claims. (o1. 22a-'zei i The invention particularly relates to a tool for trimming V,off the abutting ends of a piston ring so that said `ring will havea circumferential gap which is suliiciently large to properly t its particular companion cylinder and prevent said ring from being restrained against radial movement under any operating conditions, said circumferential gap being at the same time sufficiently. small to prevent an undue leakage of gas past the piston ring. q I

'I'heobject of the invention is to provide a simple, inexpensive and convenient tool of this character which will be capable of accurately trimming the. ends of either a square ended, a

l5 bevel ended, or a step ended piston ring of any diameter andof anycrosS-sectional shape.

In the accompanying drawng:

Figure l is a side elevation of the tool with one end thereof partially broken away with a square ended piston ring in place thereon.

Figure 2 is anendelevation ofthe tool with the same square ended type of piston ring in place thereon;v y n v i Figure 3 is a vertical, longitudinal section of g5 the tool taken on line 3--3 Fig. 4, and also showing a square ended piston ring in place thereon. 5 Figure 4 is atop plan view of the tool without any piston ring in place' thereon. A l y i Figure 5 isa fragmentary top plan of the tool showing how the tool is adjusted to trim the ends of a bevel ended piston ring.;` Y Figure 6` is a fragmentary, vertical, longitudinal section of the tool showing how it is adjusted-to trim the ends of a step ended piston ring. l

Figure 'l is a side elevationof the circular le which constitutes the trimming member of the tool..

In the following description similar characters of reference indicate like partsin the several fig- V4to urlesofthe draWlIlg-V l l, I I

L vThe base Ill Vof the .l invention is preferably of inverted cup shape,` having` aV flat. horizontal "upper face. or floorII., disposed upon a downwardly and outwardly ared, supporting portion I2,

Vterminating at its =lower peripheral edge in an annular,v outwardly extendingV flange I3. This `base is preferably .clampedto some `heavy stationary object, such as to a work bench or directly to the particular cylinder block which is being fitted with piston rings This clamping may be effected by an angle plate I4 which is secured tothebase In: by a bolt I5 and is prevented from twisting laterally out of position relatively to said base by being received'within a Vslot Iliformedradially '55 in the lower part of the basel I0, The outer end of said angle plate is drilled at I1 to receivea bolt I8 extending up from the work bench, cylinder block or other stationary objectto -which the tool is clamped.

J ournaled horizontally and longitudinally in 5 said base is a trimming member shaft 20 which is adapted to be manuallyrotatedby means of a detachable handle 2I heldinplace by a. headless set screw 22 Whose inner end bears againsta fiattened portion 23 of said handle 2l. The inner 10 end of this shaft 20 is reduced to form an annular shoulder f 2 4 and is threaded inwardly of said shoulder 24 toV receive a nut. 25. Clamped between said nut 25 and shoulder 24 are a pair of washers 25 between which is sandwiched a diskl5 shaped,` two faced, file or other trimming'member 21.v Said trimming member projects up through `the fioor II of the base IIJ through a suitable rectangular clearance aperture 28. Y y

The most convenient manner of rotatingthe `20 shaft 20 is to swing the handle 2I in a clockwise direction, as seen in Fig. 2.` The screw thread at the inner end of said shaft 20 is the ordinary right-handed thread'. By reason of these two facts, it follows that, vwhenthe disk-shaped trim- `25 ming member 21 is in operation and is therefore subjected to a resistance, it will tend to-,frictionally move the washers 26 and the Anut 25 `in `a counter-clockwise direction as seen in Fig. 2 `relatively to the shaft 2U. rIhis 'causes said nut- 25 30 to be tightenedon said shaft 20, and obviatesthe necessity of tightening up said nut extremely tight and yet permits thedis -shaped trimming member 21 to carry a heavy torque load without slipping. This construction also eliminates the need V 35 of a keyway or other relatively expensive construction to prevent said trimmingmember turning relatively to said shaft.

The upper face of the iioor II of the base I0 is annularly and concentrically countersunk at 30 40 to receive a disk-shaped, rotatable table 3I. The latter is prevented from lifting up out of position by a holding down screw 32 and a clamping screw 33. ,Said vholding'down screw 32 issecured to the upper face of the base I0 adjacent the front edge of the rotatable table 3l and slidably bears with Vthe lower face of its head against the upper face of .said table. The threaded shank of the clamp screw 33 is received within a suitable 4 50 .tapped hole 24 formed in the base lil, said shank passing through an arcuatel slot 35 suitably formed in the rotatable table 3 I. Thus, by loosening the clamping screw 33,"said rotatable table 3l may Vbe swung to any `desired position about its ,55

teo

concentric axis and then held iirmly in tightening said clamping nut 33.

The indexing of said rotatable table 3| is facilitated by three radial indexing grooves 36, 31, 38, grooves 36 and 38 being each marked 45 which indicates forty-ve degrees, while groove 31 is marked 90 which indicates ninety degrees. Anyone of these three indexing grooves 36, 31 or 38 (for instance groove 31 as shown in Figs. 1-4) isadapted to index withwa stationary index groove 40 formed radially in the top face of the rbase I0.

To permit said rotatable table 3| to be swungto either of its extreme positions without interference by the trimming member 21, Vsaidrrotatabl'e table 3| is suitably cut away segmentally at` 4| place by Arranged diametrically on the upper face'of the K/ rotatable table 3| is a vertical, half=diskshaped face plate Y42 whose lower end is bent sharply rearward to form the flanges 43 which are secured to the rotatable table 3| by spot welding 44 or otherwise. y

. Secured to and projecting perpendicularly out rfrom said face plate 42 at equal distances .from theaxisof rotat'io'n of thetable 3| is a pair of horizontal locating 'pins 45 which are parallel with eachother and lie in the same horizontal plane. 'Ihese'locating pins 45 are adapted to properly position any type or diameter of piston ring in correct alignment relatively to the rotary trimming member 21. For instance, inv Figs. 1-3 is'sho'wn a piston ring 46 which is of the plain butt orlsquareended type. This piston ring 46 is supported, upon the locating pins 45 in the manner shown in Fig. 1, the square ends of said piston ring'being forced into contact with the trimming 'member 21 by a suitable manual or other pressure indicated by the arrows 41. While the piston ring is in this position, the handle 2| is rotated, thereby causing vthegrotatable trimming inember`21 vtolikewise be rotated. Said trimhiring wheel is providedfwl-th either an abrasive 'ora cutting surface so'as' to enable'it to grind, cut or 'iotherwise trim .off the Vde'siredamount .of metal-fromthe ends of thepiston ring. The contactfjbetween said piston ringand the locating pins45 isa point contact..y By reason-of this fact, a piston ring `iis located in correct alignment relatively to the rotary trimrr'iing.memberY 21 irrefspe'ctiveof the 'diameter of vthe piston ring.

11n Fig. 1, for'instance, is shown in full lines a relatively smalL-square Vended, piston-ring 46, while in'dotted lines is shown a larger, square "endedipi'ston ring'Mil. In both cases it will be notedthat (if the thickness Vof the rotary trimf min'gllmember 21'be neglected) the ends of both sies of piston ring are trimmed off on a planek which intersects the axis of `the piston ring in vquestion. -This means that when either of the piston rings-isV compressed'into position in its companion cylinder, theA gap Vbetween. the ends .of' the piston ring (usually .010 ".01l") is of ei/' enthickness. Y

YItshould alsabe ,noted that @Verl if the one `r other size of piston ring is not held back firmly VJagainst the face plate 42,Y the trimming'of of the. adjacent ends of "the piston 'ring will bein a "piane'iterseetmg "the axis of the ring. k1r the :piston 'ring 'thus tipped relatively to the face `pla' te'42it'is'preferable ltotip the upper end out 'sofas to Icompel'theabutting ends at the lower endof the pistonjringjtdbear :rmly'against `jsaid"l`aceplate` andthereby prevent any tendency o f the piston ring to "chatter, This `is 'because' the trimming member 'doof the base l0.

Vmember journaled horizontally in 21 urges the adjacent ends of the piston ring toward said face plate when the handle 2| is rotated in a clockwise direction, as seen in Fig. 2.

The present invention is also adapted to trim the ends of a bevel ended piston ring 46a. such as that shown in Fig. 5, in which the ends of said piston ring are bevelled at 45. To enable the present invention to trim the ends of such a ring the clamp screw 33 is loosened and the table 3| rotated in the onejor other direction (depending upon which way the bevel of the ring slopes) until either the rotatable table index groove 36 or 38 registers with the stationary index groove Theclamping screw 33 is now ltightened and said piston ring 46a trimmed in 4substantially the same manner as that shown in Figs. l-4; the only diierence in this case being that the face plate '52 is disposed at an angle relatively to the rotary trimming member 21.

In Fig. 6 is shown how the invention is used to trim the endsof a step 'ended piston ring 46h. In this case `the'rotarytable"3| set as in Figs. 1-4, i. e., with the rotary table index=groove 31 in register with thestationary index groovel 40 of the base Ill. f The present invention-cansuccessfully employ any type of rotary' trimming ymember 21 whether of the abrasive or of the cutting type. It has been found, however,`that `inasmuch ras piston rings are constructed of cast gray iron, of rotary trimming wheelis -'one constructed similarly Yto an ordinary iile, the preferred form of which lis shown detached inl Fig. 7. This consists of a circular steel disk which is suitably perforated axially soas toslide'over the shaft 20 andfis deep, radially,-lgang milled in `four directions at right angles to each-*other to form the ldeep'milledtlle the besttype I teeth 56 and is shallow, radially, gang milled in four directionsv at right Aangles to eachother to form the shallow milled le teeth 5| Saidshallow rnille'di teeth 5`| are 'formed at 45 'to the 'deep-'milled teeth 50. Where the deep milled teeth 5|) overlap the shallow milled teeth 5|V there Vis caused theiformation of triangular areas having Ybastard teeth 52. fSuch bastard teeth can be formed even if thedepth of the `milled-teeth 50 isequal to the depth of 'the milled teeth 5|. It is preferred,` however, that the one set (50) of milled teethbe deeper than the other lset (5|) of lmilled teeth, so that the bastard teeth 52 will be p-rismatic in "formand "therefore strong rather than pyramidal in form and -therefore weak. :Such a-constructionr re'sultsin a rotary trimming fmember i which `may be considered 'f' a combination oflm'illedile and bastard le. iSuch a rotary-trimming Vmember 'having such milled and bastard teeth on both of its faces has proven very 'satisfactoryvin' actual service.

1. A tool for trimming piston =rings and the like comprising: a base having an vupper :horizontal face -which isv circular-ly countersunk; a circular rotatable table arranged-within lsaid `circularly countersunk surface A"and having vits circular edge vin engagement 'with thefcircular shoulder of the countersunk v-portiom'of said base; a. trimming vsaid base; -a

face plate.v connected I with ksaid table: and

Emeans for' holding the .piston "ring upon said face plate to enable said'ring toibecut'bythe-trimming a-O member.

2. M001 frtrimming piston rings and'thef like comprising: a'basef-having an upper horizontal facevwhichV is circularlycountrsunk; a circular .rotatable table arranged iwithin saidc'ircularly countersunk surface and having its circular edge in engagement with the circular shoulder of the countersunk portion of said base; a trimming member journaled horizontally in said base; a vertical face plate connected with said table; and means for holding the piston ring upon said face plate to enable said ring to be cut by the trimming member.

3. A tool for trimming piston rings and the like comprising: a base having an upper horizontal face which is circularly countersunk; a circular rotatable table arranged within said circularly countersunk surface and having its circular edge in engagement with the circular shoulder of the countersunk portion of said base; a trimming member journaled horizontally in said base on on axis lying in a vertical plane which intersects the vaxis of said table; a face plate connected with said table; and means for holding the piston ring upon said face plate to enable said ring to be cut by the trimming member.

4. A tool for trimming piston rings and the like comprising: a base having an upper horizontal l face which is circularly countersunk; a. circular rotatable table arranged within said circularly countersunk surface and having its circular edge in engagement with the circular shoulder of the countersunk portion of said baise; a trimming member journaled horizontally in said base and projecting up through said table; a face plate connected with said table; and means for vholding the piston ring upon said face plate to enable said ring to be cut by the trimming member.

5. A tool for trimming piston rings and the like comprising: a base having an upper horizontal facewhich is circularly countersunk; a circular rotatable table arrangedwithin said circularly countersunk surface and having its circular edge in engagement with the circular shoulder of the countersunkportion of said base; a face plate connected with said table; a trimming member journaled horizontally in said base and projecting up through said base and up into said face plate; and means for holding the piston ring upon said face plate to enable said ring to be cut by the trimming member.

6. A tool for trimming piston rings and the like comprising: a base having an upper horizontal face which is circularly countersunk; a circular rotatable table arranged Within said circularly countersunk surface and having its circular edge in engagement with the circular shoulder of the countersunk portion of said base; a trimming member journaled horizontally in said base and projecting up through said table through a double segmental clearance opening formed in said table; a face plate connected with said table; and means for holding the piston ring upon said face plate to enable said ring to be cut by the trimming member.

JOHN ZILLIOX. 

